Device for automatically adjusting the bacterial inoculum level of a sample

ABSTRACT

Various embodiments of the present invention provide, for example, a system and method for automatically adjusting the inoculum level of a sample. Certain embodiments of the present invention may measure a concentration of particles present in a preliminary sample using a sensor device and determine an amount of diluent to be added to or removed from a sample container to prepare a sample having a selected concentration of particles, corresponding to a selected inoculum level. Embodiments of the present invention may also automatically add or remove the diluent using an automated fluidics system so as to prepare a sample having the selected particle concentration. Once the selected particle concentration is achieved and verified, some embodiments may also remove at least a portion of the sample from the sample container such that the container contains a selected volume of the sample.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.13/016,040, filed Jan. 28, 2011, which application is a divisional ofU.S. patent application Ser. No. 11/691,662, filed Mar. 27, 2007, whichissued as U.S. Pat. No. 7,901,624 on Mar. 8, 2011, which claims thebenefit of the filing date of the U.S. Provisional Application No.60/847,244, filed Sep. 26, 2006, the disclosures of which areincorporated herein by reference.

FIELD OF THE INVENTION

The various embodiments of the present invention relate generally todevices for preparing bacteria samples having a standard selectedinoculum level characterized for example, by a selected particleconcentration.

BACKGROUND OF THE INVENTION

Micromethods for the biochemical identification of microorganisms havebeen utilized for many years. For example, several early publicationsreported the use of reagent-impregnated paper discs and micro-tubemethods for differentiating enteric bacteria. Furthermore, interest inminiaturized bacterial identification systems led to the introduction ofseveral commercial systems in the late 1960's. These early miniaturizedbiochemical identification systems provided advantages such as requiringlittle storage space, providing extended shelf life, providingstandardized quality control, and being relatively easy to use.

The modern broth microdilution test used today has origins in the tubedilution test used as early as 1942 to determine in vitro antimicrobialsusceptibility testing (AST) of bacterial isolates from clinicalspecimens. The broth dilution technique involves exposing bacteria todecreasing concentrations of antimicrobial agents in liquid media byserial two-fold dilution. The lowest concentration of an antimicrobialagent in which no visible bacterial growth occurs is defined as theminimal inhibitory concentration (MIC). The MIC is the standard measureof antimicrobial susceptibility.

The introduction in 1956 of a microtitrator system, using calibratedprecision spiral wire loops and droppers for making accurate dilutionsrapidly, allowed the development of a serial dilution AST test. Themicrotitrator system was accurate and allowed the reduction in volumesof antimicrobial agents. The term “microdilution” appeared in 1970 todescribe MIC tests performed in volumes of 0.1 mL or less ofantimicrobial solution.

Several commercially-available systems automate the microdilutionprocess for MIC/AST testing. For example, the assignees of the variousembodiments of the present invention provide a panel-based system(available commercially as the Phoenix™ ID/AST System) capable ofperforming 100 AST and bacterial identification tests at one time. Suchsystems include a disposable comprising a sealed and self-inoculatingmolded polymer tray having 136 microwells containing dried reagents. Thetray includes: (1) a bacterial identification (ID) side including driedsubstrates for bacterial ID; and (2) an AST side having varyingconcentrations of antimicrobial agents, as well as growth andfluorescent controls at appropriate microwell locations.

In such ID/AST systems, the bacterial ID side utilizes a series ofchromogenic and fluorogenic biochemical tests to determine theidentification of a bacterial organism. Both growth-based and enzymaticsubstrates are employed to cover different types of reactivity withinthe range of taxa that may be present in a given sample. These ID testsare based on microbial utilization and subsequent degradation ofsubstrates detected by various indicator systems. Acid production isindicated by a change in phenol red indicator when an isolate is able toutilize a carbohydrate substrate. Furthermore, chromogenic substratesproduce a yellow color upon enzymatic hydrolosis of either p-nitrophenylor p-nitroanilide compounds. Enzymatic hydrolosis of fluoregenicsubstrates results in the release of a fluorescent coumarin derivative.Bacterial organisms that utilize a specific carbon source reduce theresazurin-based indicator. In addition, other tests are provided on thebacterial ID side to detect the ability of a bacterial organism tohydrolyze, degrade, reduce, or otherwise utilize a given substratepresent in the microwells of the bacterial ID side.

Furthermore, the AST side of panel-based systems utilizes broth-basedmicrodilution. For example, the Phoenix™ system utilizes a redoxindicator for the detection of organism growth in the presence of agiven antimicrobial agent. Continuous measurements of changes to theindicator, as well as bacterial turbidity measurements (as describedfurther herein) may be used in the determination of bacterial growth.Each AST panel configuration contains several antimicrobial agents witha wide range of two-fold doubling dilution concentrations. Organism IDis used in the interpretation of MIC values of each antimicrobial agent.

Such panel-based systems are conventionally provided as a disposablecomponent of an overall ID/AST system (such as the Phoenix™ system, forexample). In such systems, the disposable panels must be exposed to asample having a selected organism density (defined, for example, by theturbidity of the sample relative to the McFarland (McF) scale). Forexample, the Phoenix™ system often utilizes panels that have beeninoculated with a targeted organism density of either 0.25 McF or 0.5McF.

Thus, the effective use of ID/AST systems requires the manualpreparation of a panel inoculum having a selected concentration ofparticles (expressed as a turbidity, for example) that is standardizedrelative to the McFarland scale. Therefore, improvements in inoculumpreparation and handling are desirable.

SUMMARY OF THE INVENTION

Embodiments of the present invention may include a system forautomatically preparing a sample (such as an inoculum, for example)having a selected concentration of particles (corresponding to aselected bacterial density, for example) and/or a selected volume. Inone embodiment, the system comprises a fluidics system configured forreceiving a sample container containing a preliminary sample, whereinthe fluidics system is further configured for adding a diluent to thesample container and/or removing at least a portion of the preliminarysample from the sample container. The system also comprises a sensordevice (such as a nephelometer, for example) configured for measuring aconcentration of particles in the preliminary sample and a controllerdevice in communication with the fluidics system and the sensor device.The controller device may be configured for receiving the measuredconcentration of particles from the sensor device and determining anamount of diluent to be added to the sample container and/or an amountof the preliminary sample to be removed from the sample container toprepare the sample having the selected concentration of particles (whichmay be expressed, in some embodiments, as a turbidity measurement). Thecontroller device may be further configured for controlling the fluidicssystem to add the determined amount of diluent to the sample containerand/or remove the determined portion of the preliminary sample from thesample container so as to prepare the sample having the selectedconcentration of particles. Furthermore, the controller device may befurther configured for controlling the fluidics system to remove atleast a portion of the sample from the sample container such that thesample container contains the sample having the selected volume. In someembodiments, the controller device may comprise a user interfaceconfigured for receiving a user input comprising at least one of theselected concentration of particles and/or the selected volume of thesample.

In some embodiments, the system may be further configured for receivinga testing container corresponding to the sample container. According tosuch embodiments, the fluidics system may be further configured fortransferring at least a portion of the sample having the selectedconcentration of particles and/or the selected volume to the testingcontainer. Furthermore, in some such embodiments, the fluidics systemmay be further configured for dispensing an indicator substance in thetesting container and subsequently mixing at least a portion of thesample and the indicator substance in the testing container.

In some system embodiments, the fluidics system may be configured formixing the preliminary sample and/or the completed sample. For example,in some embodiments, the fluidics system may be further configured formixing the preliminary sample before determining the concentration ofparticles suspended therein. The fluidics system may also be furtherconfigured for mixing the sample having the selected concentration ofparticles prior to removing at least a portion of the sample from thesample container.

Some system embodiments may further comprise a robotic system incommunication with the controller device. The robotic system may beconfigured for moving at least one of the sample container, the testingcontainer, the fluidics system, and the sensor device relative to oneanother. In some such embodiments, the system may further comprise arack defining an ID aperture configured for receiving the samplecontainer and a testing aperture configured for receiving the testingcontainer. In some system embodiments, at least one of the samplecontainer and the rack may comprise a unique indicator affixed thereto,wherein the unique indicator corresponds to an identity of thepreliminary sample and/or a selected concentration of particles presentin the prepared sample. In various system embodiments, the uniqueindicator may include, but is not limited to: a bar code; analphanumeric label; an RFID label; and other indicator that may bereadable, for example, by downstream processing elements such as aninterface configured for transferring a prepared sample to anidentification and anti-microbial susceptibility testing system, asdescribed further herein.

In some system embodiments, the robotic system may be further configuredto receive the rack for moving at least one of the sample container andthe testing container relative to the fluidics system and the sensordevice. For example, in some system embodiments, the robotic system maybe configured for moving through a range of motion defined at least inpart by an X-axis, a Y-axis, and a Z-axis. In such embodiments, therobotic system may comprise a shuttle device configured for moving therack along the X-axis.

In some system embodiments comprising a rack defining an ID apertureconfigured for receiving the sample container, the rack may furthercomprise a sample container receptacle configured for receiving thesample container, wherein the sample container receptacle is slidablydisposed in the ID aperture. In some such embodiments, the shuttledevice may comprise a floor defining a sensor device aperture located atan analysis position (along the X-axis, for example). Furthermore,according to such embodiments, the sensor device may be disposed withinthe sensor device aperture such that as the rack is moved to theanalysis position, the ID aperture is substantially co-located with thesensor device aperture. Therefore, the sample container receptacle maybe inserted into the sensor device aperture and adjacent to the sensordevice such that the sensor device is capable of measuring theconcentration of particles in the preliminary sample contained in thesample container. In some such embodiments, the rack may furthercomprise a biasing element operably engaged between the rack and thesample container receptacle, configured for biasing the sample containerreceptacle towards a top surface of the rack. In some such embodiments,the system may further comprise a robotic device configured for operablyengaging the sample container receptacle and/or urging the samplecontainer receptacle towards a bottom surface of the rack and into thesensor device aperture when the rack is moved to the analysis position.

In some system embodiments, comprising a robotic system, the system mayfurther comprise a dispensing tip station comprising a plurality ofdisposable dispensing tips. In such embodiments, the robotic system maybe configured for automatically replacing a dispensing tip operablyengaged with the fluidics system with at least one of the plurality ofdisposable dispensing tips after preparing the sample having theselected concentration of particles and/or the selected volume.

In some system embodiments, the robotic system may further comprise afirst robotic device comprising a first fluidics head in fluidcommunication with the fluidics system. The first robotic device may beconfigured for moving along at least one of the Y-axis and the Z-axissuch that the first fluidics head is capable of adding the diluent tothe sample container and/or removing at least a portion of thepreliminary sample from the sample container as the shuttle device movesthe rack to a filling position along the X-axis.

Furthermore, the robotic system may also comprise a second roboticdevice configured for carrying the sensor device (which may comprise anephelometer in some embodiments) along the Z-axis so as to position thesensor device adjacent to the sample container along the Z-axis, suchthat the sensor device is capable of measuring a concentration ofparticles suspended in the preliminary sample within the samplecontainer as the shuttle device moves the rack to an analysis positionalong the X-axis. In some embodiments, the system and/or the secondrobotic device may further comprise a sheath surrounding the sensordevice. According to some such embodiments, the sheath may be configuredto cooperate with a channel defined about the ID aperture in the rack toprovide a substantially light tight environment about the samplecontainer and the sensor device when the second robotic device positionsthe sensor device adjacent to the sample container when the rack ismoved to the analysis position. The second robotic device may also, insome embodiments, further comprise a second fluidics head in fluidcommunication with the fluidics system. In such embodiments, the secondfluidics head may be configured for adding a diluent to the samplecontainer and/or removing at least a portion of the preliminary samplefrom the sample container so as to prepare the sample having theselected concentration of particles suspended therein.

According to some system embodiments comprising a second robotic device,the system may further comprise a wash station configured for receivingthe sensor device and/or the second fluidics head (wherein one or bothof which may be carried by the second robotic device, for example). Insuch embodiments, the wash station may be further configured for washingat least one of the sensor device and the second fluidics head duringand/or between sample-preparation cycles.

Various embodiments of the present invention may also comprise aninterface configured for transferring the sample having the selectedconcentration of particles to an identification and anti-microbialsusceptibility testing (ID/AST) system configured for analyzing thesample so as to identify at least one bacterial component of the sampleand/or to determine a susceptibility of the at least one bacterialcomponent to an anti-microbial compound. Furthermore, some systemembodiments may comprise an ID/AST system configured for analyzing thesample so as to identify at least one bacterial component of the sampleand/or determine a susceptibility of the at least one bacterialcomponent to an anti-microbial compound. According to some suchembodiments, the interface and/or the integrated ID/AST system may beconfigured for reading a unique indicator affixed to at least one of therack and the sample container such that the identified at least onebacterial component may be traceable to the preliminary sampleoriginally contained in a particular sample container and/or rack. Asdescribed herein, the unique indicator may also correspond, at least inpart, to a selected concentration of particles in the prepared sample.

Various embodiments of the present invention also provide methods (andin some embodiments, corresponding computer program products) forautomatically preparing a sample having a selected concentration ofparticles and/or a selected volume in a sample container containing apreliminary sample. In one embodiment, the method comprises steps formeasuring a concentration of particles suspended in the preliminarysample using a sensor device (which may, in some embodiments, comprise anephelometer) and subsequently determining an amount of diluent to beadded to the sample container and/or an amount of the preliminary sampleto be removed from the sample container to prepare the sample having theselected concentration of particles using a controller device incommunication with the sensor device. Various method embodiments mayalso comprise steps for adding the determined amount of diluent using anautomated fluidics system in communication with the controller and/orremoving the determined amount of the preliminary sample from the samplecontainer, so as to prepare the sample having the selected concentrationof particles using an automated fluidics system in communication withthe controller device. Some method embodiments of the present inventionfurther comprise a step for removing at least a portion of the preparedsample from the sample container using the automated fluidics system,such that the sample container contains a sample having the selectedvolume. As described herein with respect to the various systemembodiments of the present invention, a controller device may comprise auser interface. Therefore, some method embodiments may further comprisea step for receiving a user input comprising at least one of theselected concentration of particles and the selected volume of thesample via a user interface in communication with the controller device.

Some method embodiments further comprise a step for transferring atleast a portion of the sample having the selected concentration ofparticles and/or the selected volume to a testing containercorresponding to the sample container using an automated fluidicssystem. According to some such embodiments, the method may furthercomprise steps for dispensing an indicator substance in the testingcontainer using the automated fluidics system and mixing the at least aportion of the sample and the indicator substance in the testingcontainer using the automated fluidics system. Some method embodimentsmay also further comprise various mixing steps using the automatedfluidics system. For example, some method embodiments may furthercomprise steps for mixing the preliminary sample before determining theconcentration of particles suspended in the preliminary sample and/ormixing the sample having the selected concentration of particles priorto removing at least a portion of the sample from the sample container.

Some method embodiments may further comprise steps for reducing orpreventing the cross-contamination of various sample containers andtesting containers. For example, some method embodiments may furthercomprise replacing a dispensing tip operably engaged with the automatedfluidics system with at least one of a plurality of disposabledispensing tips stored in a dispensing tip station, after removing atleast a portion of the sample from the sample container. Furthermore,some method embodiments may further comprise washing the sensor deviceusing a wash station configured for receiving the sensor device when itis not in use.

Thus the various embodiments of the present invention provide manyadvantages that may include, but are not limited to: providing a systemand method for automatically preparing a sample having a standardizedand substantially accurate concentration of particles suspended therein(characterized as a turbidity measured against the McFarland scale, forexample); providing a system and method for preparing multiple samplesthat reduces or prevents cross-contamination between samples; providinga system and method for preparing multiple samples that is compatiblewith and/or incorporates existing substantially-automated bacterialidentification and AST testing systems and routines.

These advantages, and others that will be evident to those skilled inthe art, are provided in the systems and methods of the variousembodiments of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Having thus described various embodiments of the invention in generalterms, reference will now be made to the accompanying drawings, whichare not necessarily drawn to scale, and wherein:

FIG. 1 shows a non-limiting schematic of the operation of a system forautomatically preparing a sample having a selected turbidity level and aselected volume, according to one embodiment of the present invention;

FIG. 2 shows a non-limiting perspective view of a tray configured tocarry a plurality of sample containers and a corresponding plurality oftesting containers in a system for automatically preparing a samplehaving a selected turbidity level and a selected volume, according toone embodiment of the present invention;

FIG. 3 shows a non-limiting perspective view of a system forautomatically preparing a sample having a selected turbidity level and aselected volume, according to one embodiment of the present invention;

FIG. 4 shows a non-limiting detailed perspective view of the interactionof a second robotic device, carrying a nephelometer and a fluidics headsurrounded by a light-shielding sheath, with a channel defined in ansample container tray, according to one embodiment of the presentinvention;

FIG. 5 shows a non-limiting side-view of a system for automaticallypreparing a sample having a selected turbidity level and a selectedvolume, according to one embodiment of the present invention;

FIG. 6 shows a non-limiting top-view of a system for automaticallypreparing a sample having a selected turbidity level and a selectedvolume, according to one embodiment of the present invention;

FIG. 7 shows a non-limiting detailed perspective view of a secondrobotic device, carrying a nephelometer and a fluidics head surroundedby a light-shielding sheath, operably engaged with a channel defined inan sample container tray to form a substantially light-tight environmentaround the sample container for a turbidity measurement, according toone embodiment of the present invention;

FIG. 8 shows a non-limiting schematic of the steps of a method andcomputer program product for automatically preparing a sample having aselected turbidity level and a selected volume;

FIG. 9 shows a non-limiting schematic of the steps of a method andcomputer program product for automatically preparing a sample having aselected turbidity level and a selected volume, comprising steps formeasuring turbidity, determining a diluent amount, dispensing a diluent,and removing a portion of a sample, according to one embodiment of thepresent invention;

FIG. 10 shows a non-limiting perspective view of a shuttle device,according to one embodiment of the present invention, comprising a floordefining a sensor aperture;

FIG. 11 shows a non-limiting perspective view of a rack, according toone embodiment of the present invention, comprising a sample containerreceptacle configured for receiving the sample container;

FIG. 12 shows a non-limiting cross-sectional view of a rack located anat analysis position such that the sample container receptacle may belowered in to the sensor device aperture; and

FIG. 13 shows a non-limiting perspective view of an interface configuredfor transferring the sample having the selected concentration ofparticles to an identification and anti-microbial susceptibility testingsystem configured for analyzing the sample.

DETAILED DESCRIPTION

The present inventions now will be described more fully hereinafter withreference to the accompanying drawings, in which some, but not allembodiments of the invention are shown. Indeed, these inventions may beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein; rather, these embodiments areprovided so that this disclosure will satisfy applicable legalrequirements. Like numbers refer to like elements throughout.

The various embodiments of the present invention are described herein inthe context of an environment for preparing bacterial samples having astandard level characterized by a selected density for use withdownstream ID/AST processes that analyze samples placed in ID/ASTdisposable trays including: (1) a bacterial identification (ID) sideincluding dried substrates for bacterial ID; and (2) an AST side havingvarying concentrations of antimicrobial agents, as well as growth andfluorescent controls at appropriate microwell locations. However, itshould be understood that the various systems 1, methods and computerprogram products described herein may be utilized for producing avariety of different sample types having a selected particleconcentration (characterized by a turbidity measurement, for example)and/or a selected volume. For example, various embodiments of thepresent invention may be utilized to produce and/or replicate a solutionhaving a selected particle concentration (measured, for example, as aturbidity level relative to a McFarland standard) comprising apreliminary sample of latex particles suspended in a sterile salinediluent. In other embodiments, the automated sensor device 200, fluidicssystem 100, and controller device 300 may be used to produce and/orreplicate a McFarland standard (such as a 0.5 McFarland standard)comprising 0.05 mL of 1.175% barium chloride dehydrate (BaCl₂.2H₂O) and9.95 mL of 1% sulfuric acid (H₂SO₄).

Some embodiments of the present invention may comprise a system 1 forautomatically preparing a sample having a selected concentration ofparticles suspended therein and/or a sample having a selected volumethat may be optimized for use with downstream processes (such as anID/AST procedure, for example). As shown generally in FIG. 1, the system1 may comprise a fluidics system 100 configured for receiving a samplecontainer 10 (see FIG. 2, for example) containing a preliminary sample(such as a bacterial sample taken from one or more media plates). Itshould be understood that the preliminary sample may be prepared usingautomated and/or manual processes. For example, in some embodiments, apreliminary sample of inoculum may be prepared for downstream ID/ASTprocesses. According to some such exemplary embodiments, ID/AST panelsample may be prepared by picking bacterial colonies of the samemorphology with the tip of a sterile cotton swab from one of severaldifferent media plates and manually depositing such colonies in a testtube filled with sterile media. The resulting bacterial samples may thenbe suspended in a sample container 10 and vortexed for a selected periodof time.

As further described herein with respect to FIGS. 4-6, the fluidicssystem 100 components of the various system embodiments described hereinmay be further configured for adding a diluent to the 10 and/or removingat least a portion of the preliminary sample from the sample container10. As described further herein, the fluidics system 100 may comprise aplurality of different fluidics heads 435, 425 in fluid communicationwith a supply of diluent (such as a sterile saline reservoir, forexample) such that the fluidics system 100 is capable of dispensing thediluent to one or more of the sample containers 10 and/or testingcontainers 20. Furthermore, the fluidics system 100 (and the variousfluidics heads 435, 425 in fluid communication therewith) may also beconfigured to be capable of aspirating, mixing, and/or vortexing thepreliminary samples and/or the produced samples having a selectedturbidity level during the operation of the system 1. Furthermore, andas further described herein, the fluidics system 100 may also be capableof operably engaging one or more disposable dispensing tips 510 (seeFIG. 5 showing a system 1 comprising a dispensing tip station 500 fromwhich a disposable dispensing tip 510 may be “picked” by a firstfluidics head 425 operably engaged with a first robotic device 420).

The fluidics system 100 may, in some embodiments, comprise an automatedpipettor system that makes use of the disposable dispensing tips 510 toprevent cross-contamination of various ID tubes 10 (and correspondingtesting tubes 20). In such embodiments, the pipettor may perform fluidtransfer of a diluent from a storage container (such as a reservoircomprising saline solution, for example) to the sample container 10thereby allowing the preliminary sample (comprising a bacterial sample,for example) to be diluted to a selected concentration of particles(corresponding to a McFarland value). The pipettor may also level thefluid level of the sample container 10 (and/or remove a portion of thesample to achieve a selected volume) and transfer a predetermined amountof the sample having the selected turbidity level from the samplecontainer 10 to an associated testing container 20 (such as an ASTcontainer, for example). The pipettor may also be configured to add anindicator substance (i.e. an AST indicator dye) to the testing container20. In some system 1 embodiments including a fluidics system 100comprising an automated pipettor, the pipettor may also perform varioussample mixing steps or functions by performing various aspirate anddispense cycles. In some embodiments, the fluidics system 100(comprising an automated pipettor, for example) may also be configuredfor aspirating the preliminary sample and/or the prepared sample havinga selected concentration of particles so as to measure a volume of thesample.

In some embodiments, the fluidics system 100 (which may be embodied as apipettor system carried by one or more components of the robotic system400) may comprise one or more sensor tips (such as capacitive pipettetips having capacitive sensors embedded therein for detecting a presenceof an ionic fluid (such as the preliminary sample and/or preparedsample)). The sensor tip, in cooperation with the controller device 300described herein, may be configured for determining a volume ofpreliminary sample and/or prepared sample in the sample container 10.For example, in some embodiments, such sensor tips may be carried by acomponent of the robotic system 400 that is capable of moving through arange of motion relative to the Z-axis 403 (see FIG. 4, for example).Because the sensor tip is capable of sensing the presence of thepreliminary sample (or other ionic fluids) in the sample container 10,and because the maximum volume of the standard sample container 10 isknown (and may be programmed into the controller device 300), theposition of the robotic system 400 component carrying the sensor tipalong the Z-axis 403 may be indicative of the total volume ofpreliminary sample and/or prepared sample in the sample container 10.Thus, according to such embodiments, the sensor tip carried by therobotic system 400 (and in communication with the fluidics system 100)may allow for the precise determination of volume within the samplecontainer 10. The determination of a selected volume of the preparedsample may be especially advantageous for preparing samples having botha selected concentration of particles therein as well as a selectedvolume that is compatible with ID/AST systems configured for determiningan identity and/or an antimicrobial susceptibility of the particlessuspended in the sample.

Furthermore, the system 1 further comprises a sensor device 200 (seealso FIG. 4 showing a sensor device 200 head carried by a second roboticdevice 430) configured for measuring a concentration of particlessuspended in the preliminary sample in the sample container 10. Thesensor device 200 may comprise an analog and/or digital opticalinstrument configured for measuring a turbidity level of a suspension ona standard scale (such as the McFarland scale, for example). Forexample, in some embodiments, the sensor device 200 may comprise anephelometer configured for generating a turbidity measurement. In otherembodiments, the sensor device 200 may comprise one or more opticaldevices configured for measuring at least one of: a scatteringparameter; a transmittance; a reflectivity; and/or another opticalparameter that may be directly and/or indirectly related to aconcentration of particles suspended in the sample. In some embodiments,the sensor device 200 may comprise one or more optical emitters(configured for generating electromagnetic energy in a visible and/ornon-visible spectrum and one/or more corresponding optical receiversconfigured for measuring a transmittance and/or reflectivity of theelectromagnetic energy incident on the sample. The sensor device 200 mayalso, in some embodiments, comprise one or more electronic interfacesfor communicating with a controller device 300 so as to be capable oftransmitting a measured concentration of particles (expressed in someembodiments as a turbidity value, for example) to the controller device300. For example, the sensor device 200 may be in wired and/or wirelesscommunication with the controller device 300 via a computer networkand/or a direct “hard-wired” connection. In some embodiments, the sensordevice 200 may be in communication with the controller device 300 viaone/or more interface components (such as RS-232 interfaces, forexample). Furthermore, in some system 1 embodiments, the sensor device200 may be “zeroed” (by placing a substantially pure saline solution inthe sample container 10 (see FIG. 7, for example) and/or calibrated to aMcFarland standard (by placing a 0.5 and/or 0.25 McFarland standardsolution in the sample container 10.

Furthermore, as shown for example in FIGS. 4 and 12 the sensor device200 may be disposed in various positions relative to other system 1components of the embodiments of the present invention. For example, insome embodiments, the sensor device 200 may be disposed in a sensordevice aperture 1020 (see FIG. 10) defined in a floor 1010 of a shuttledevice 410 that may be configured for moving a rack 50 containing one ormore sample containers 10 (as described further herein). In otherembodiments, the sensor device 200 (and/or a receiver and/or emitterportion thereof) may be carried by one or more robotic devices 430 (asshown in FIG. 4, for example).

As shown schematically in FIG. 1, the system 1 further comprises acontroller device 300 in communication with the fluidics system 100 andthe sensor device 200. The controller device 300 may be generallyembodied as a typical computer system or processing element, includingbut not limited to: a microprocessor, VLSI, ASIC, etc. The controllerdevice 300 may also comprise one or more of: a storage device (forstoring one or more selected turbidity levels, standard or calibrationturbidity levels, and/or selected volumes, for example); a userinterface 700 (comprising a display, keyboard and/or mouse interface,for example); and one/or more network interfaces configured to allow thecontroller device 300 to communicate with a wired or wireless networkand/or one or more external computer systems.

Furthermore, as shown generally in FIG. 1, the controller device 300 maybe configured for receiving the measured concentration of particlessuspended in the preliminary sample from the sensor device 200.Furthermore, the controller device 300 (and/or a processor deviceincluded therein) may be further configured for determining an amount ofdiluent to be added to the sample container 10 and/or an amount of thepreliminary sample to be removed from the sample container in order toprepare a sample having the selected concentration of particles (whichmay be pre-defined by the controller device 300 and/or received by thecontroller device 300 via a user interface 700). For example, thecontroller device 300 (and/or a processor included therein) may beconfigured for calculating the amount of diluent that should be added tothe sample container 10 and/or an amount of the preliminary sample to beremoved from the sample container in order to prepare a sample having aselected turbidity (based at least in part on the relationship of themeasured turbidity to the turbidity of a McFarland standard, forexample).

Furthermore, the controller device 300 may also be further configuredfor controlling the fluidics system 100 (and one or more fluidics heads425, 435 and/or automated pipettors in fluid communication therewith) toadd the determined amount of diluent to the sample container 10 and/orto remove the determined amount of the preliminary sample from thesample container 10 so as to prepare the sample having the selectedturbidity level. Furthermore, the controller device 300 may be furtherconfigured for controlling the fluidics system 100 to remove (viaaspiration, for example) at least a portion of the sample from thesample container 10 such that the sample container 10 contains theselected volume of the sample having the selected turbidity. Asdescribed herein, the controller device 300 may also be in communicationwith one or more components 410, 420, 430 of a robotic system that maybe configured to carry and/or manipulate various parts of the fluidicssystem 100 (and/or various fluidics heads 425, 435) in relation to thesample container 10.

As shown generally in FIG. 5, in some system 1 embodiments, the fluidicssystem 100 may be further configured for receiving a testing container20 (such as an antimicrobial susceptibility testing (AST) container, forexample) corresponding to the sample container 10 (see also FIG. 2,showing a tray 50 configured to carry a plurality of sample containers10 and a corresponding plurality of testing containers 20). The fluidicssystem 100 (and, in some embodiments, a first fluidics head 425 in fluidcommunication therewith and carried by a first robotic device 420) maybe further configured for transferring at least a portion of the samplehaving the selected turbidity level and the selected volume from thesample container 10 to the testing container 20. In some system 1embodiments, the fluidics system 100 may be further configured fordispensing an indicator substance (such as an optimized colorimetricredox indicator, for example) in the testing container 20 andsubsequently mixing the at least a portion of the sample and theindicator substance in the testing container 20. In such embodiments,the system 1 may further comprise a reservoir containing a supply ofindicator substance that may be removed and/or dispensed by an automatedpipettor device and/or a fluidics head 425 carried by a first roboticdevice 420. Furthermore, the various components of the fluidics system100 may also mix the indicator substance with the sample by performing aseries of aspirate and dispense cycles.

The fluidics system 100 may also be configured for performing a numberof other mixing functions during the operation of the variousembodiments of the system 1. As described herein, the fluidics system100 may, in some embodiments, perform such mixing functions byperforming a number of aspirate and dispense cycles with the samplecontainer 10 and/or the testing container 20. For example, in somesystem embodiments, the fluidics system 100 may be further configuredfor mixing the preliminary sample in the sample container 10 beforedetermining the turbidity level of the preliminary sample (see, forexample, step 804 shown in the system 1 and/or method flow chart of FIG.8). In other system 1 embodiments, the fluidics system may be furtherconfigured for mixing the sample having the selected turbidity levelprior to removing at least a portion of the sample from the samplecontainer 10 (see, for example, step 808 shown in FIG. 8).

As shown generally in FIGS. 1, 3, 5 and 6, the system 1 may furthercomprise various components 410, 420, 430 of a robotic system 400 incommunication with the controller device 300. As shown schematically inFIG. 1, the robotic system 400 may be configured for moving at least oneof the sample container 10, the testing container 20, the fluidicssystem 100, and the sensor device 200 relative to one another. In orderto facilitate the positioning and movement of a discrete number ofsample containers 10 (and, in some embodiments, corresponding testingcontainers 20 using the robotic system 400, the system 1 may alsocomprise a rack 50 as shown in FIG. 2. In some embodiments, the rack 50defines an ID aperture 51 configured for receiving the sample container10 and a testing aperture 52 configured for receiving the testingcontainer 20.

In some system 1 embodiments, at least one of the rack 50, the samplecontainer 10, and the testing container 20 may comprise a uniqueindicator affixed thereto, wherein the unique indicator corresponds tothe selected concentration of particles and/or to an identity of thepreliminary sample contained within a particular container 10, 20 Insuch embodiments, the unique indicator may comprise a machine-readableindicator and/or various other unique indicators that may include, butare not limited to: a bar code; an alphanumeric label; an RFID label;and/or combinations of such indicators. As described further herein,such unique indicators may be read by at an interface 1310 station (seeFIG. 13) and/or by a downstream ID/AST system such that the sampleprepared and/or analyzed by the various system 1 embodiments of thepresent invention may be traceable to a particular rack 50 and/or samplecontainer 10 (that may be further traceable back to a particularbacterial sample, for example, via the unique indicator). In embodimentswherein the unique indicators comprise machine-readable indicators (suchas bar code and/or RFID-encoded information) the system 1 (and/or thecontroller device 300 thereof) may be configured for periodicallyreading the unique indicator for tracking the progress of a particularsample and/or bacterial sample as it is processed by the various system1 embodiments of the present invention.

As shown in FIG. 11, the unique indicator 1150 may be operably engagedwith a rotatable status wheel 1120 that may be further operably engagedwith the rack 50. The status wheel 1120 may comprise a plurality ofsides each comprising a unique indicator 1150 corresponding, forexample, to a particular selected concentration of particles (asmeasured, for example, by the sensor device 200 when the rack 50 isadvanced to an analysis position (as shown generally in FIG. 12)). Therack 50 may define a status window 1130 such that only one of aplurality of unique indicators 1150 are visible to a user (and/or adownstream indicator reader (such as a bar-code scanner, for example))at any one time. As shown in FIG. 12, the system 1 may comprise anrotating actuator 1127 configured for selectively engaging a stem 1125of the status wheel 1120 when the rack 50 is at a particular positionwithin the system 1 (such as an analysis position with respect to thesensor device 200 (as shown generally in FIG. 12)). The rotatingactuator 1127 may be in communication with the sensor device 200 (viathe controller device 300, for example) such that the rotating actuator1127 may be responsive to the concentration of particles (expressed insome embodiments as a turbidity) determined by the sensor device 200.Therefore, in some embodiments, the rotating actuator 1127 may beconfigured for rotating the status wheel 1120 relative to the rack 50such that the unique indicator 1150 that is visible via the statuswindow 1130 defined in the rack 50 substantially corresponds to theselected concentration of particles (expressed, for example, asturbidity on the McFarland Scale) in the prepared sample.

As shown generally in FIG. 6, the robotic system 400 (and/or a shuttledevice 410 thereof, comprising an X-axis 401 shuttle device) may befurther configured to receive the rack 50 for moving at least one of thesample container 10 and the testing container 20 relative to thefluidics system 100 and the sensor device 200. For example, as showngenerally in FIG. 6, the robotic system 400 may comprise a shuttledevice 410, comprising register devices (such as indentations sized forreceiving the rack 50) for receiving and carrying the rack 50 along theX-axis 401 of the system 1 to one or more positions relative to a firstrobotic device 420 and/or a second robotic device 430 as describedfurther herein, such that these various components of the robotic system400 may operate sequentially on the sample container 10 (and the samplecontained therein) to produce a sample having a selected concentrationof particles and/or a selected volume.

As shown generally in FIG. 10 the shuttle device 410 may comprise adrive belt 1030 configured for carrying the rack 50 along the X-axis 401of the system 1 to one or more positions relative to a first roboticdevice 420 and/or a second robotic device 430 as described furtherherein. The shuttle device 410 may also comprise one or more conveyors1040 configured for advancing the rack 50 in an entrance queue along theY-axis 402, for example. In some embodiments the shuttle device 410 (andassociated conveyors 1040) may carry the rack 50 in a substantially“U-shaped” path from entrance queue (shown in the left side of thesystem 1 embodiment shown in FIG. 6, for example) to the X-axis 401pathway defined by the shuttle device 410, and finally to an exit queue(shown in the right side of the system 1 embodiment shown in FIG. 6, forexample).

As shown generally in FIG. 10, in some embodiments, the shuttle device410 may comprise a floor 1010 defining a sensor device aperture 1020located at an analysis position along the X-axis 401. According to suchembodiments (and as shown in further detail in the cross-sectional viewof FIG. 12, for example), the sensor device 200 may be mounted and/ordisposed within the sensor device aperture 1020 such that as the rack 50is moved to the analysis position along the system's X-axis 401 thesample container 10 may be lowered into the sensor device aperture 1020via the ID aperture 51 (which, in some embodiments, may extendcompletely through the thickness of the rack 50 assembly (as shown inFIG. 12, for example). Referring to FIGS. 11 and 12, in some suchembodiments, the rack 50 may comprise a sample container receptacle 1110configured for receiving the sample container 10. As shown particularlyin FIG. 12, the sample container receptacle 1110 may be slidablydisposed in the ID aperture 51 such that the sample container 10 may beurged downward through the rack 50 and into the sensor device aperture1020 such that the sensor device 200 may measure a concentration ofparticles suspended in the sample contained within the sample container10. In some such embodiments, the rack 50 may further comprise a biasingelement 1210 operably engaged between the rack 50 and the samplecontainer receptacle 1110. In some embodiments, the biasing element 1210may comprise a spring configured for biasing the sample containerreceptacle 1110 towards a top surface 1101 of the rack 50.

In some embodiments, the system may further comprise a robotic device(such as, for example, the second robotic device 430 shown in FIG. 4).The robotic device may be configured for operably engaging the samplecontainer receptacle 1110 so as to urge the sample container receptacle1110 (and the sample container 10 held therein) towards a bottom surface1102 of the rack 50 and into the sensor device aperture 1020 defined inthe floor 1010 of the shuttle device 410 when the rack 50 is moved tothe analysis position. In such embodiments, because the sensor device200 is substantially enclosed in a low-light environment (within thesensor device aperture 1020, for example), a substantially light-tightenvironment may be established about the sensor device 200 and thesample container 10 when the robotic device urges the sample containerreceptacle 1110 downward and into the sensor device aperture 1020. Thus,according to such embodiments, the second robotic device 430 need notcarry the sensor device 200 as shown in FIG. 4. However, as describedfurther herein, a sheath 432 (see FIG. 4, for example) may be includedin such embodiments, as the sheath 432 may operably engage the samplecontainer receptacle 1110 so as to urge the sample container receptacle1110 downward and into the sensor device aperture 1020.

Furthermore, in some such embodiments (as shown generally in FIG. 4) therobotic device (comprising the second robotic device 430, for example)may comprise a fluidics head 435 in fluid communication with thefluidics system 100, wherein the fluidics head 435 is configured foradding a diluent to the sample container 10 and/or removing at least aportion of the preliminary sample from the sample container 10 so as toprepare the sample having the selected concentration of particles.

As shown generally in FIG. 3, in some system 1 embodiments, the roboticsystem 400 may comprise various components 410, 420, 430 configured tomove through a range of motion defined at least in part by an X-axis401, a Y-axis 402, and a Z-axis 403. According to some such embodiments,the robotic system 400 may comprise a shuttle device 410 (as describedherein with respect to FIG. 10, for example) configured for moving therack 50 along the X-axis 401. As described herein, the shuttle device410 may comprise, in some embodiments, a linear actuator deviceconfigured for movement substantially along a linear axis so as to becapable of advancing the tray 50 along the X-axis 401. In some system 1embodiments, the shuttle device 410 may advance (and/or “index”) therack 50 to a series of predetermined “stop” positions along the X-axis401 such that each pair of sample containers 10 and correspondingtesting containers 20 may be serviced by the first and second roboticdevices 420, 430 (and the fluidics heads 425, 435 and sensor 200 carriedthereby) in a substantially linear fashion until all the containers 10,20 carried by the rack 50 have been processed to produce a series ofsamples having a selected concentration of particles suspended thereinand/or a selected volume that may be compatible, for example, with oneor more downstream ID/AST processes (such as, for example, the Phoenix™ID/AST system produced by the assignee of the present application).Furthermore, and as described herein, the shuttle device 410 may defineone or more register devices for centering and/or operably engaging therack 50 on the shuttle device 410. For example, the shuttle device 410may define one or more channels or indentations for receiving acorresponding surface of the rack 50. In other embodiments, the shuttledevice 410 may comprise one or more posts or brackets configured toreceive a corresponding corner or side wall of the rack 50 such that theshuttle device 410 may effectively position and/or index the rack 50relative to various components of the system 1. As shown in FIG. 10, theshuttle device 410 may also comprise one or more drive belts 1030configured for carrying the rack 50 along the X-axis 401 of the system 1to one or more positions relative to a first robotic device 420 and/or asecond robotic device 430 as described further herein. The shuttledevice 410 may also comprise one or more conveyors 1040 configured foradvancing the rack 50 in an entrance and/or exit queue along the Y-axis402, for example.

In some embodiments, the shuttle device 410 (and/or an exit queueconveyor thereof, for example) may be operably engaged with an interface1310 (such as a “pouring station” as shown generally in FIG. 13). Theinterface 1310 may be configured for receiving the rack 50 so as tofacilitate the transfer of the processed sample having the selectedconcentration of particles to an identification and anti-microbialsusceptibility testing (ID/AST) system configured for analyzing thesample so as to identify at least one bacterial component of the sampleand/or determine a susceptibility of the at least one bacterialcomponent to an anti-microbial compound. For example, the interface 1310may be operably engaged with an output queue of the robotic system 400so as to be capable of receiving a rack 50 containing a plurality ofsample containers 10 and a corresponding plurality of testing containers20.

In some embodiments, the interface 1320 may comprise a substantially“stand-alone” organization station configured for aligning each of apair of sample containers 10 and testing containers 20 with acorresponding ID/AST disposable that may be placed face-down in one ormore registers 1320 configured to receive a corresponding one or moreID/AST disposables (such as, for example, a Phoenix™ ID/AST disposablemanufactured by the assignees of the present application). As showngenerally in FIG. 13, the registers 1320 defined in the interface 1310may be in fluid communication with one or more pouring aperturesconfigured for receiving the processed samples from the samplecontainers 10 and testing containers 20 disposed in the rack 50. Theinterface 1310 may thus provide a convenient organizing station where auser may easily view and/or verify the unique indicator 1150 that may beoperably engaged with a rotatable status wheel 1120 that may be furtheroperably engaged with the rack 50. As described herein, the uniqueindicator 1150 may selectively indicate a particular selectedconcentration of particles of the prepared sample contained in one ofthe sample container 10 and the testing container 20 (as measured, forexample, by the sensor device 200 when the rack 50 is advanced to ananalysis position (as shown generally in FIG. 12)). Thus, the interface1310 may allow a user to quickly view and/or evaluate the uniqueindicator 1150 (either visually or using a bar code scanner, forexample) to ensure that the prepared sample contained in one of thesample container 10 and the testing container 20 includes the selectedconcentration of particles that is substantially compatible with theID/AST disposable before applying the prepared sample to thecorresponding ID/AST disposable contained, for example, in one or moreof the registers 1320. As shown in FIG. 13, the pouring station 1310 mayalso comprise an inclined portion 1330 configured for orienting theregisters 1320 (and therefore, any ID/AST disposables held therein) atan optimal angle such that the prepared samples poured from the samplecontainer 10 and/or the testing container 20 may advance completelythrough various fluidic pathways that may be defined in an ID/ASTdisposable to reach one or more microwells containing dried substratesfor bacterial ID and/or growth and fluorescent controls.

Furthermore, some system embodiments of the present invention may alsocomprise an identification and anti-microbial susceptibility testing(ID/AST) system configured for receiving the sample having the selectedconcentration of particles. For example, the system 1 may comprise anintegrated ID/AST system (such as the Phoenix™ ID/AST system produced bythe assignees of the present application) that is configured to receive,for example, one or more ID/AST disposables that may be exposed to oneor more of the samples produced according to the process shownschematically in FIGS. 8 and 9 using, for example, the system 1 showngenerally in FIG. 3. As described herein, such ID/AST systems may befurther configured for identifying at least one bacterial component ofthe sample (i.e. an “ID” determination) and/or determining asusceptibility of the at least one bacterial component within the sampleto an anti-microbial compound (i.e. an “AST” process). The ability ofthe various system 1 embodiments of the present invention to prepare asample having a precise concentration of particles (corresponding to aparticular optimal bacterial density, for example) may be especiallyhelpful in generating usable AST results. The ID/AST system maycomprise, for example, a Phoenix™ ID/AST system disclosed generally inU.S. Pat. No. 6,096,272, which is hereby incorporated by referenceherein in its entirety.

In some system 1 embodiments (as shown generally in FIG. 5), the roboticsystem 400 may also comprise a first robotic device 420 comprising afirst fluidics head 425 in fluid communication with the fluidics system100. The first robotic device 420 may be configured for moving along atleast one of the Y-axis 402 and the Z-axis 403 (so as to be capable ofraising and/or lowering the first fluidics head 425 relative to at leastone of the sample container 10 and the testing container 20). Thus,using the first fluidics head 425 (which may comprise an automatedpipettor) the first robotic device 420 may be capable of adding thediluent to the sample container 10 and/or removing at least a portion ofthe preliminary sample from the sample container 10 (via aspiration, forexample) as the shuttle device 410 moves the rack 50 to a fillingposition along the X-axis 401 (substantially adjacent to the Y-axis 402travel of the first robotic device 420, for example). In some system 1embodiments, the first robotic device 420 may comprise one or morelinear actuator configured for advancing and/or retracting one or morefluidics heads 425 along the Y-axis. For example, in some embodiments,the first robotic device 420 may comprise one or more “ZY robots”configured for movement independently along the Y-axis 402 and theZ-axis 403. In such embodiments, as shown generally in FIG. 5, forexample, the ZY robots of the first robotic device 420 may be capable ofpositioning the first fluidics head 425 above at least one of: the IDand testing containers 10, 20 held in the rack 50; a dispensing tipstation 500; and a waste container 650 (configured for receiving excessdiluent and/or sample material aspirated from one or more containers 10,20 using the first fluidics head 425). According to some suchembodiments, the system 1 may further comprise a dispensing tip station500 comprising a plurality of disposable dispensing tips 510. In somesuch embodiments, the robotic system 400 (and more particularly, thefirst robotic device 420) may be configured for automatically replacinga dispensing tip 510 operably engaged with the fluidics system 100(and/or with a first fluidics head 425 carried by the first roboticdevice 420) with at least one of the plurality of disposable dispensingtips 510 after preparing the sample having the selected turbidity leveland the selected volume. In other system 1 embodiments, the roboticsystem 400 may be configured for automatically replacing a dispensingtip 510 operably engaged with the fluidics system 100 with at least oneof the plurality of disposable dispensing tips 510 after transferring atleast a portion of the sample from the sample container 10 to thetesting container 20 and mixing the indicator substance with the sample.Thus, the first robotic device 420 may be capable of utilizing a newdisposable dispensing tip 510 for the various dispense and aspiratecycles used to process the sample having the selected turbidity leveland selected volume for each new sample container 10 (and correspondingtesting container 20) as the shuttle device 410 indexes the tray 50along the X-axis 401 of the system 1.

In some additional system 1 embodiments, the robotic system 400 mayfurther comprise a second robotic device 430 configured for carrying thesensor 200 along the Z-axis 403 (i.e. for raising and lowering thesensor device 200 relative to the sample container 10 (see FIGS. 4 and7, for example) so as to position the sensor device 200 adjacent to thesample container 10 along the Z-axis 403. Thus, the second roboticdevice 430 may be configured for optimally positioning the sensor device200 for measuring a turbidity level of the preliminary sample in thesample container 10 as the shuttle device 410 moves the rack 50 to ananalysis position along the X-axis 401. In some system 1 embodiments, asshown generally in FIG. 4, the rack 50 may further define a channel 55about the ID aperture 51 that may be sized and configured to receive acomplementary sheath 432 that is operably engaged with the secondrobotic device 430. The sheath 432 may be positioned so as tosubstantially enclose the sensor device 200 (and/or a scanning headthereof) such that when the second robotic device 430 lowers the sensordevice 200 along the Z-axis 403 and into position substantially adjacentto the ID tube 10, the sheath 432 is configured to entering the channel55 defined in the tray 50 so as to provide a substantially light tightenvironment about the sample container 10 and the sensor device 200.Thus, the sheath 432 may be configured to shield the sensor device 200from ambient light present in the environment where the system 1 isoperating such that the sensor device 200 is better capable of providingmore accurate turbidity readings of the sample disposed in the samplecontainer 10.

As shown in FIGS. 4 and 7, the second robotic device 430 may alsocomprise a second fluidics head 435 in fluid communication with thefluidics system 100. In some system 1 embodiments, the second fluidicshead 435 may comprise an automated pipettor device (as described hereinwith respect to other components of the fluidics system 100 and thefirst fluidics head 425). The second fluidics head 435 may be configuredfor adding a diluent to the sample container 10 (in a dispense cycle)and/or removing at least a portion of the preliminary sample from thesample container 10 (in an aspirate cycle, for example) so as to preparethe sample having the selected concentration of particles. As describedherein with respect to other system 1 embodiments, the second fluidicshead 435 may also be capable of mixing the sample in the samplecontainer 10 by performing one or more aspirate and dispense cycles(see, for example, the “mix and verify target density achieved” (McF)step shown as step 808 of FIG. 8).

As shown in FIG. 6, the second robotic device 430 may comprise a roboticarm configured for moving about a central axis to a selected angularposition Θ relative to the central axis of the robotic arm. Thus, inembodiments wherein the second robotic device 430 comprises a secondfluidics head 435 the second robotic device 430 may be configured to becapable of moving through an angle Θ and/or moving along the Z-axis 403to obtain a supply of diluent from a diluent reservoir (containing, forexample, a supply of sterile saline solution) and swing through theangle Θ to a position adjacent to the sample container 10 so as to becapable of dispensing the diluent into the sample container 10.Furthermore, in some embodiments, as shown in FIG. 6, the system 1 mayfurther comprise a wash station 600 configured for receiving the sensordevice 200 and the second fluidics head 435 when the second roboticdevice 430 is not in use. The wash station 600 may be further configuredfor washing at least one of the sensor 200 and the second fluidics head435 between dispensing, aspirating, and/or measuring cycles when thesecond robotic device 430 is “parked” in the wash station 600.

As shown in FIG. 3, some system 1 embodiments may further comprise auser interface 700 integrated with and/or in communication with thecontroller device 300. The user interface 700 may be configured forreceiving a user input comprising at least one of the selectedconcentration of particles and/or the selected volume of the sample.According to various system 1 embodiments, the user interface 700 maycomprise a display (such as a touch-screen LCD, for example) and/orother user interface components including, but not limited to: akeyboard/keypad; a mouse/trackball; and alarm elements (such as speakersand/or indicator lights). The user interface 700 may thus also beconfigured for allowing a user to monitor and/or control the operationof the system 1. For example, the user interface 700 may provide visualand/or auditory feedback to a user regarding system 1 status. Suchfeedback may include, but is not limited to: diluent-level sensing;alarms; disposable dispensing tip 510 inventory status; tray 50 positionstatus; sample container 10 and/or testing container 20 inventory; andother system 1 monitoring feedback.

As shown generally in FIGS. 8-9, various embodiments of the presentinvention may also provide methods for automatically preparing a samplehaving a selected concentration of particles (expressed, in someembodiments, as a turbidity level, for example) and/or a selected volumein a sample container 10 containing a preliminary sample. As showngenerally in FIG. 9 the method may first comprise step 805 for measuringa concentration of particles suspended in the preliminary sample using asensor device 200. The method further comprises step 806 for determiningan overall dilution scheme that may comprise, for example, an amount ofdiluent to be added to the sample container 10 to prepare a samplehaving the selected concentration of particles, and/or an amount of thepreliminary sample to be removed from the sample container 10 prior toadding diluent, to avoid any overflow from the sample container 10,using a controller device 300 in communication with the sensor device200. In addition, the method further comprises step 807 for adding thedetermined amount of diluent and/or removing the determined amount ofpreliminary sample determined in step 806 using an automated fluidicssystem 100 in communication with the controller device 300, so as toprepare a sample having the selected concentration of particlessuspended therein. Finally, in some embodiments, the method furthercomprises step 810 for removing at least a portion of the sample fromthe sample container 10 using the automated fluidics system 100, suchthat the sample container 10 contains the sample having the selectedvolume. It should be understood that the methods shown, for example, inFIGS. 8 and 9 may be performed by a substantially automated system.

FIG. 8 shows another exemplary embodiment of the methods of the presentinvention including additional method steps that may be performed inorder to prepare a sample having a selected concentration of particlesand/or a selected volume in a sample container 10 containing apreliminary sample. It should be understood that the steps depictedgenerally in FIG. 8 (especially the selected concentration of particles(shown in terms of a turbidity measured against the McFarland (McF)scale)) steps 806-806 a as well as step 807, are specific to exemplarysamples having selected turbidity levels of either 0.25 McF or 0.5 McF,respectively which may outline selected particle concentrations that aresuitable for use in downstream ID/AST processes such as those performedby the Phoenix™ ID/AST system produced by the assignees of the presentapplication (which may be set to utilize samples having a density ofeither 0.25 McF or 0.5 McF depending at least in part on the type ofbacteria or other particles that are targeted for identification and/ortesting to determine antimicrobial susceptibility). It should be furtherunderstood that various method embodiments of the present invention maybe used to prepare samples having a variety of selected concentrationsof particles and/or volumes other that those exemplary values shown inFIG. 8.

As shown in FIG. 8, various method embodiments may further comprise step801 for loading consumables into a system 1 such as that systemdescribed generally herein with respect to FIG. 1. The consumables mayinclude, but are not limited to: disposable dispensing tips 510; diluent(such as bulk sterile saline solution, for example); and indicatorsubstance (such as bulk AST indicator substance that may be dispensedinto a testing container 20 as part of step 812, for example). Themethod may further comprise step 802 for loading a rack 50 with apreliminary sample (contained, for example, in a sample container 10,such as an ID tube). Once the consumables and sample rack 50 are loaded,the process may be initiated (see, for example, element 800 denoting theprocess start). The method may further comprise, in some embodiments,step 800 a for checking an inventory and/or status of the consumables(such as AST reagent, or other consumables) before entering into thesubsequent steps for preparing a sample having a selected concentrationof particles and/or volume. As described herein with respect to varioussystem 1 embodiments of the present invention, step 800 a may beperformed by the controller device 300 and results generated by step 800a may be presented to a user in a status report and/or status indicatorcommunicated via a user interface 700 (such as a display and/or alarmindicator). Furthermore, if one or more reagents or other consumablesare not detected onboard the system, the controller device 300, in someembodiments, may automatically suspend the method shown in FIG. 8 (see,for example, element 800 b).

Furthermore, some method embodiments may further comprise step 804 formixing the preliminary sample contained in the sample container 10 priorto performing step 805 for measuring a concentration of particlessuspended in the preliminary sample (i.e. “reading” a density of thesample using a nephelometer or other sensor device 200). As shown inFIG. 8, step 804 may, in some embodiments, further comprise detecting alevel of the preliminary sample in the sample container (using, forexample, a sensor tip (i.e. a capacitive tip) in communication with thecontroller 300). Level detection in step 804 may be accomplished, forexample, by lowering one or more sensor tips into the sample container10 using one or more fluidics heads 425 carried by a robotic device(such as one or more replicates of the first robotic device 420 showngenerally in FIGS. 3 and 5). Step 804 may further comprise storing thedetected level of the preliminary sample (using, for example, a memorydevice integrated with the controller device 300) for comparison with asample container 10 fluid level obtained later in step 810. As describedherein with respect to various system 1 embodiments, any mixing step(such as step 804) may be performed by an automated fluidics system 100(such as a pipettor) in a series of aspirate and/or dispense cycles.

As shown herein with respect to FIG. 8, the method may further comprisestep 805 for measuring a concentration of particles suspended in thepreliminary sample (using a sensor device 200, such as a nephelometer,for example). Furthermore, based at least in part on the measuredconcentration of particles (expressed as a turbidity level in someembodiments), the controller device 300 described herein may be furtherconfigured to perform step 806 for determining an overall dilutionscheme (i.e. an amount of diluent to be added to the sample container 10and/or an amount of the preliminary sample to be removed from the samplecontainer 10) for preparing a sample having a selected concentration ofparticles suspended therein (and that will not overfill and/or underfilla sample container 10 having a known volume).

Thus, as shown in FIG. 8, step 806 may comprise various subroutinesand/or decision points for determining quantities of an overall dilutionscheme, which may comprise an amount of diluent to be added to thesample container 10 and/or an amount of the preliminary sample to beremoved from the sample container 10 to arrive at a sample having aselected concentration of particles suspended therein (given a measuredconcentration of particles suspended in the preliminary sample measuredin step 805). For example, in embodiments wherein the concentration ofparticles is expressed as a turbidity measurement, step 806 a maycomprise determining if the turbidity level (i.e. “density” in McF, forexample) is initially too low (i.e. below a minimum turbidity relativeto 0.25 and 0.5 McF targets, for example). If step 806 a results in apositive result (i.e. density too low), then the process may be halted(i.e. the sample container 10 may be rejected). If the density(turbidity or measured concentration of particles determined in step805) is sufficient to allow for the application of the determineddilution scheme (see step 806), then the method may progress to step 807as discussed further herein.

As shown generally in FIG. 8, step 807 generally comprises adding thedetermined amount of diluent to the sample container 10 or removing thedetermined amount of the preliminary sample from the sample container 10prior to adding diluent to prevent, for example, overflow of the samplecontainer 10 (using an automated fluidics system 100, for example) incommunication with the controller device 300, so as to prepare a samplehaving the selected concentration of particles (i.e. a sample thatcomplies substantially with the dilution scheme determined in step 806).Depending on the detected concentration of particles determined in step805 (and the corresponding dilution scheme determined in step 806), themethod may comprise adding diluent to the sample container 10 (such asbulk saline) and/or removing at least a portion of the overallpreliminary sample from the sample container 10 (which may contain bothdiluent and a portion of the sample particles suspended therein) inorder to achieve a selected target level of dilution (which maycorrespond to the selected concentration of particles in the sample). Asdescribed herein, in some embodiments, a user may select one or moretarget particle densities that may be optimal for certain types of IDand/or AST processes. For example, in some embodiments the selectedconcentration of particles may include, but is not limited to 0.25 McFand 0.5 McF. As shown in FIG. 8, step 807 may further compriseaspirating fluid from the sample container 10 (which may include diluentas well as sample particles suspended therein) in order to “reset” thelevel of the prepared sample to the volume detected originally in step804.

Step 808 may comprise mixing the sample having the selectedconcentration of particles suspended therein prior to removing at leasta portion of the sample from the sample container using the automatedfluidics system. Step 808 may be performed via one or moreaspirate/dispense cycles using the second fluidic head 435 (carried, forexample, by a second robotic device 430). As shown in FIG. 7, becausestep 808 may be performed by a second robotic device 430 carrying boththe second fluidic head 435 and the sensor device 200, step 808 may alsocomprise verifying the concentration of particles suspended therein(using the sensor device 200) of the sample prior to removing at least aportion of the sample from the sample container 10 using the automatedfluidics system 100.

As shown generally in step 809, the controller 300 (and/or a userperforming the method embodiments described herein) may read theverified concentration of particles determined in step 808 and eitherreject the tube (if the measured concentration of particles from step808 is not substantially equivalent to the selected concentration ofparticles) or proceed with the downstream method steps 810-816. Somemethod embodiments may further comprise step 810 for verifying the fluidlevel (i.e. a level of the preliminary sample) in the sample container10 using a second sensor tip (i.e. a disposable capacitive tip carriedby one or more fluidics heads 425 operably engaged with a robotic device420). As described herein, the robotic system 400 may comprise, in someembodiment, a pair dedicated robotic devices 420 wherein one of therobotic devices is tasked with performing the steps 808 and 809 (i.e.performing the dispense and/or aspiration steps mandated by the dilutionscheme determined in step 806) and the other robotic device isresponsible for transferring a portion of the prepared sample to acorresponding testing container 20 for AST sample preparation (see steps811-814). Thus, the second “AST” preparation robotic device 420 maycomprise a separate fluidics head 425 carrying a second sensor tipconfigured for independently verifying the level of the prepared samplein the sample container 10 prior to transferring at least a portion ofthe prepared sample to the corresponding testing container 20.

FIG. 8 also shows an additional method step 811 for determining if atesting container 20 is present that may correspond to a given samplecontainer 10. If not, the method ends at step 811. However, if a testingcontainer 20 is present, the method may proceed to steps 812-814 whichcomprise steps for preparing a testing container 20 for downstream ASTprocesses, for example, by adding and/or mixing an indicator substanceto a portion of the sample having the selected concentration ofparticles and/or volume. It should be understood that in various methodembodiments, steps 812-814 may be performed by one or more components ofa fluidics system 100 as part of a complete system 1 as describedherein. Step 812 comprises dispensing an indicator substance in thetesting container 20 using the automated fluidics system 100 and mixingusing the automated fluidics system 100. Step 813 comprises transferringat least a portion of the sample having the selected concentration ofparticles and/or the selected volume to a testing container 20corresponding to the sample container 10 using the automated fluidicssystem 100 and mixing the at least a portion of the sample and theindicator substance in the testing container 20 using the automatedfluidics system 100. As described herein with respect to several system1 embodiments, the various mixing steps performed, for example, as partof steps 812 and 813 may be performed by an automated fluidics system100 comprising an automated pipettor configured to repeatedly aspiratefrom and/or dispense to the testing container 20 in order to achieve thedesired level of mixing. Furthermore, step 814 comprises updating a rackstatus indicator (see, for example, the rotatable status wheel 1120shown in FIG. 11. As described herein with respect to FIG. 11, the step814 may be performed by a rotating actuator 1127 configured forselectively engaging a stem 1125 of the status wheel 1120 when the rack50 is at a particular position within the system 1 (such as an analysisposition with respect to the sensor device 200 (as shown generally inFIG. 12)). The rotating actuator 1127 may be in communication with thesensor device 200 (via the controller device 300, for example) such thatthe rotating actuator 1127 may be responsive to the concentration ofparticles (expressed in some embodiments as a turbidity) determined bythe sensor device 200. Therefore, in some embodiments, the rotatingactuator 1127 may be configured for rotating the status wheel 1120relative to the rack 50 such that the unique indicator 1150 that isvisible via the status window 1130 defined in the rack 50 substantiallycorresponds to the selected concentration of particles (expressed, forexample, as turbidity on the McFarland Scale) in the prepared sample.

As shown in FIG. 8, various method embodiments may also comprise step815 for determining if additional sample containers 10 are present inthe system 1. If so, the method may return to step 807 such that thedilution scheme determined in step 806 may now be applied to anothersample container 10 (which may be indexed forward in some methodembodiments by a shuttle device 410 configured for systematicallyadvancing a rack 50 containing the sample containers 10 along an axis ofthe system 1). If no additional sample containers 10 are detected instep 815, the method may proceed to step 816 for removing a completedrack 50 of sample containers 10 and corresponding testing containers 20for use in a downstream process requiring samples having a selectedconcentration of particles (such as a selected bacterial densityrequired for downstream microdilution ID/AST tests, for example).

In addition to providing systems and methods, the present invention alsoprovides computer program products for performing the various steps andcombinations of steps described above. The computer program products mayoperate via a computer-readable storage medium having computer readableprogram code embodied in the medium. With reference to FIG. 1, thecomputer readable storage medium may be part of the controller device300, and may implement the computer readable program code to perform theabove discussed steps.

In this regard, FIGS. 8-9 are block diagram, flowchart and control flowillustrations of methods, systems 1 and computer program productsaccording to exemplary embodiments of the invention. It will beunderstood that each block or step of the block diagram, flowchart andcontrol flow illustrations, and combinations of blocks in the blockdiagram, flowchart and control flow illustrations, can be implemented bycomputer program instructions. These computer program instructions maybe loaded onto a computer or other programmable apparatus (including,for example, the controller device 300 described herein) to produce amachine, such that the instructions which execute on the computer orother programmable apparatus are capable of implementing the functionsspecified in the block diagram, flowchart or control flow block(s) orstep(s). These computer program instructions may also be stored in acomputer-readable memory that can direct a computer or otherprogrammable apparatus to function in a particular manner, such that theinstructions stored in the computer-readable memory produce an articleof manufacture including instructions which implement the functionspecified in the block diagram, flowchart or control flow block(s) orstep(s). The computer program instructions may also be loaded onto acomputer or other programmable apparatus to cause a series ofoperational steps to be performed on the computer or other programmableapparatus to produce a computer implemented process such that theinstructions which execute on the computer or other programmableapparatus provide steps for implementing the functions specified in theblock diagram, flowchart or control flow block(s) or step(s).

Accordingly, blocks or steps of the block diagram, flowchart or controlflow illustrations support combinations of steps for performing thespecified functions, and program instructions for performing thespecified functions. It will also be understood that each block or stepof the block diagram, flowchart or control flow illustrations, andcombinations of blocks or steps in the block diagram, flowchart orcontrol flow illustrations, can be implemented by special purposehardware-based computer systems which perform the specified functions orsteps, or combinations of special purpose hardware and computerinstructions.

Many modifications and other embodiments of the inventions set forthherein will come to mind to one skilled in the art to which theseinventions pertain having the benefit of the teachings presented in theforegoing descriptions and the associated drawings. Therefore, it is tobe understood that the inventions are not to be limited to the specificembodiments disclosed and that modifications and other embodiments areintended to be included within the scope of the appended claims.Although specific terms are employed herein, they are used in a genericand descriptive sense only and not for purposes of limitation.

1. A computer program product for automatically preparing a samplehaving a selected concentration of particles therein and a selectedvolume in a sample container containing a preliminary sample, thecomputer program product adapted to operate a controller device incommunication with an automated fluidics system and a sensor device, thecomputer program product comprising a computer-readable storage mediumhaving computer-readable program code instructions stored thereincomprising: a first set of computer instructions for automaticallymeasuring a concentration of particles in the preliminary sample usingthe sensor device; a second set of computer instructions for determiningat least one of an amount of diluent to be added to the sample containerand an amount of the preliminary sample to be removed from the samplecontainer to prepare the sample having the selected concentration ofparticles; a third set of computer instructions for adding thedetermined amount of diluent to the sample container or removing thedetermined amount of the preliminary sample from the sample containerusing the automated fluidics system in communication with the controllerdevice, so as to prepare the sample having the selected concentration ofparticles.
 2. A computer program product according to claim 1, furthercomprising a fourth set of computer instructions for removing at least aportion of the sample from the sample container using the automatedfluidics system, such that the sample container contains the samplehaving the selected volume.
 3. A computer program product according toclaim 1, wherein the second set of computer instructions for determiningcomprises: determining if the sample having the selected concentrationof particles may be prepared by adding the determined amount of diluentwithout exceeding a maximum volume of the sample container; anddetermining if the sample having the selected concentration of particlesmay be prepared by adding the determined amount of diluent to prepare asample having at least a minimum volume.
 4. A computer program productaccording to claim 2, further comprising a fifth set of computerinstructions for transferring at least a portion of the sample havingthe selected concentration of particles and the selected volume to atesting container corresponding to the sample container using theautomated fluidics system.
 5. A computer program product according toclaim 4, further comprising: a sixth set of computer instructions fordispensing an indicator substance in the testing container using theautomated fluidics system; and a seventh set of computer instructionsfor mixing the at least a portion of the sample and the indicatorsubstance in the testing container using the automated fluidics system.6. A computer program product according to claim 5, further comprisingan eighth set of computer instructions for mixing the preliminary sampleusing the automated fluidics system before determining the concentrationof particles in the preliminary sample.
 7. A computer program productaccording to claim 6, further comprising a ninth set of computerinstructions for mixing the sample having the selected concentration ofparticles using the automated fluidics system prior to removing at leasta portion of the sample from the sample container.
 8. A computer programproduct according to claim 7, wherein the automated fluidics systemcomprises a dispensing tip station comprising a plurality of disposabledispensing tips, the computer program product further comprising a tenthset of computer instructions for replacing a dispensing tip operablyengaged with the automated fluidics system with at least one of theplurality of disposable dispensing tips after removing at least aportion of the sample from the sample container.
 9. A computer programproduct according to claim 8, further comprising an eleventh set ofcomputer instructions for washing the sensor device using a wash stationconfigured for receiving the sensor device.
 10. A computer programproduct according to claim 9, further comprising a twelfth set ofcomputer instructions for receiving a user input comprising at least oneof the selected concentration of particles and the selected volume ofthe sample via a user interface in communication with the controllerdevice.